The Basement Helicopter Finally Got Interesting | Basement Mosquito Helicopter Ep. 29

Added: 2026-05-10

[00:00:00]This video is going to be all over the place and I'm sorry for that. I'll do my best to keep it as clear as possible.

[00:00:05]But by the end of this video, hopefully all this stuff will be fully assembled.

[00:00:09]It will be on the helicopter and we will be ready to install the engine when it gets here next week.

[00:00:31]Up until now, basically every mechanical assembly was just handtightened and put together for fitment. And that was because I didn't want to get anything permanently installed because I knew I was going to have to paint the helicopter. And that's still partially true. The helicopter is completely primerred. It's ready to be sanded and painted. But I've decided I'm going to fully assemble this helicopter in the current state with it in primer. Um, and then I'll take everything back off in basically big sim assemblies and then paint the helicopter then. So that means I need to tear down basically everything that I've done already, fully assemble it so that it's ready to go on the helicopter and then get everything installed there pretty much to the point where it can fly. We'll go ahead and start with the mast assembly. So, where I left off last time, this square push tube uh was actually pretty tight in these Teflon collars. Uh, and so since then, I've polished that tube so it would slide a little bit easier. And I did a little bit more fine sanding on the ID of that collar. That push tube is now free to slide, which is a good thing. But the next step is to drill and tap four holes into each one of those collars so that we can secure that collar in place and make sure it doesn't move or rotate uh while it's on the helicopter.

[00:02:16]Next up is this butterfly assembly. If you remember from the first time when I assembled this, I didn't like the stackup that happened in here. If you got the bearings tight, these rod ends were loose. And if you got the rod ends tight, then the bearing was loose. And so I didn't like that. So, I ended up doing after a lot of screwing around and is I I found these uh 10,000 quarter inch shims, basically quart-inch washers that are 10,000 thick um and playing around with it a whole bunch of times.

[00:02:44]Uh the solution that worked for me, probably won't work for everyone, but uh no shims in the middle. If you put shims in the middle of the two bearings down in there on the inside, it will bind up the bearings. So, you don't want any shims between the bearing. And then I put a 10,000 shim on each side of the rod end. And all of this is tight and nice and clean. So that's what I would suggest you do. Uh you may have to use a different stackup, but that's what worked for me. We'll get this installed into this little Y piece and then that one will be complete.

[00:03:27]Next is to install these two push rods that go through the mast and then eventually get down to the swash plate.

[00:03:33]They go through the two teflon sleeves and there's two holes which they pass through. Um after you press this teflon into the mast, um the holes actually go und sized. So I ended up drilling it out to a size H drill bit. Uh when I used a quarter inch, it still was just a little bit too tight. So I bought a real sharp H drill bit. It's slightly oversized, and that um was basically perfect for the amount of clearance that I needed for these to slip through those bushings. I started to go throw a uh lock nut on here in reverse and thread this into one of these rod ends. And it gets stuck about a thread uh in. And I check the thread. The thread's accurate.

[00:04:16]Um I know a/4 28 threads into my rod end. Uh, and so I can only assume that the coating that's on this push rod is basically filling up the threads and blocking it from going it in. So I went out and I grabbed a die, a/428 die. So we're going to throw that die down these threads, clean them up a little bit, and then everything should go as planned.

[00:04:40]Chasing those threads solved that problem. I went ahead and I got these push rods pushed up in through their teflon bushings and threaded into the top rod end up here. I did play around with it a little bit to make sure that the amount of thread engagement at the top would be similar to or as close to the same uh as the thread engagement down at the bottom. This mechanism makes basically a parallelogram. And so you can't really screw this up and there's no right or wrong length for those push rods. Uh, basically you want to make sure that the uh, butterfly assembly at the top is as level as possible. And then you can adjust the lower rod ends uh, while you're fishing a bolt through the eyes to basically make sure that they're aligned and that bolt should slide in as free as possible. If you don't have those three bolts aligned, the bolt won't go in and so you need to adjust accordingly. Once then the bottom three uh rod ends should be also parallel to the top butterfly and you should be good to go. The mast assembly is complete. Everywhere I have castle nuts, I'm either going to go back and pull those bolts out and drill those bolts or I'll just buy pre-drilled uh a fasteners that will work with those castle nuts. So, that's not quite finished, but it is finished enough. Uh next up is the three control tubes that go down to the control mixer. These are made with um 3/4 inch I think this is 3/4 inch uh tubes 35 and a half inches long. You can see here that I've already polished three of them. This is actually what uh it looks like unpolished. So I spent a little bit of time making them look pretty. From there uh they provide you with these threaded collars. These collars get pushed into the end of all three push rods. I'm going to get some masking tape over the polished rods just to protect those. We have to mark where the three rivets are going to go on each end of each rod. Uh, and then I will cut this all thread so that those are all 3-in lengths. Once the six studs are cut and deburred, you have to get a lock nut on each end from opposite directions.

[00:06:48]That will then be the jam nut that goes into the control rod and into the rod end. Three rivets hold each collar inside each tube. Those are evenly spaced radially. And then actually they're actually offset by about a quarter inch. That way the tail end of those rivets don't actually interfere inside the tube. It's pretty important that these three tubes are exactly the same length or as close as possible. And so I used a 1, two, three block that I measured out and clamped down to the workbench. Test fit each one individually and threaded them in until they just barely fit between those two blocks. With the control tubes fabricated and to the correct length, we can now get them installed onto the swash plate. And then once they're installed onto here, we can feed all of that down into the helicopter and get the mast mounted. Quick side note, another mosquito builder, Jackie, turned me on to making drill fixtures with 3D printed parts, and I have fully embraced this. For me, it takes about the same amount of time to throw something together in CAD as it does to mark it out on the part. And when you have a 3D printed jig, you can't screw it up. I fully encourage you to do so.

[00:08:38]I've got the three control tubes now basically dangling down where they're supposed to be. And next is the extremely frustrating and daunting task of getting those rod ends connected onto this mixer where they're supposed to go.

[00:08:52]I was going to attempt to videotape how I did that. Oh my god, this is going to be miserable.

[00:09:00]No way. But I would have ended up with like 2 hours of footage and 5 seconds of usable footage [laughter] because it is just a nightmare. It is impossible to get uh the washers in the places where you need to get them because one, you're back there blind. You can't orient it in a way that the washers won't fall out and it's just it's a nightmare. Long story short, so it's in there now. Good luck to anyone who has to do that in the future. Unfortunately, that will be me one more time before we're done with this. But we're going to move on to the actual control tubes, uh which will connect our uh joystick up to the front.

[00:09:44]All right, I had to get all of this installed so that I could explain what the heck is going on here. So, I'm going to go back and show clips of basically how we got here. But, in short, I'm doing things a little bit different. I wanted my pivot point for my joystick to be in a very specific location. Uh, which is a little bit different than the manual. the manual basically you put all these things in and it drives that location. Um, so I've chosen it. Other than that, most of this is basically the same. But in short, I knew that I wanted that location to be 4 and 1/2 in forward of this bulkhead. 4 and 12 in is going to get uh drilled into this aluminum tube. And that tube basically places the front rod end, which is the anchor of this four bar mechanism or how this all works. Uh without the last bar and without this anchor, none of this will work. So this last bar's length is fairly critical. Um so to make sure that we get this rod the right length, you have to make sure all the other mechanisms are all in their neutral position to give you the best shot.

[00:10:50]There is some adjustability back here, so we will be okay, but um we're trying to get it as close as we can. First things you need to do is make sure that your collective is in the neutral position. So you can go up and down.

[00:11:05]Make sure visually that it's kind of in the middle of the travel. From there, the second step is to make sure your swash plate is as level as possible. You do that by messing with the butterfly linkage and then spinning the mast around in circles until your swash plate stops wobbling. That basically tells you it's in the neutral position. From there, these control rods go down and they actually transfer through a few of these holes in here. Uh you can grab then the uh upper portion of this mixer and push it back and forth and see where it clashes and then get in the middle of its travel for its location. Once you have all of those mechanisms in their spot, the final thing to do is to get this lower rod installed. This is the roll rod and the anchor again. Uh, and then from there you can mark the end of that rod and that is where you should be cutting it.

[00:12:02]One last small but extremely critical note. Uh, when you're drilling the hole in this lower roll tube, the hole that goes through it has to be 100% parallel to the back flange where your rod ends mount for the push rods that go up to the swash plate. If those are not the same, everything will be crooked.

[00:12:27]So, I've screwed this up already just trying to use a drill press and I don't trust myself. So, I 3D printed a jig.

[00:12:35]And this is actually it's um for 1/4 in and for 3/16. Uh the hole is actually 1 in spaced from the end. So, uh the 3/16 comes from this end and then the 1/4 in comes from the other end. And then I also have these weird features. So, this is a flat face. So, once I put this onto the control tube, I can put the um this billet piece, the end that needs to be flat on one end on a 123 block. And then I can put this fixture over here on this other one 123 block. And that will ensure that they are 100% in the same plane. I can then tape that up and use this as a guide so I can make sure that I get directly in the middle of the tube. And my hope is that it'll get to be a perfect drilled uh hole in that cross tube so that my stick will stick straight up. No pun intended.

[00:13:33]And there it is. The cyclic roll bar is fixed into the helicopter. The roll works as it should. It pivots the swash plate up there. And because this anchors that four bar mechanism, now the collective works as it should as well.

[00:13:49]The next and final step for the controls is to get the cyclic pitch rod installed. This is pretty straightforward. This is basically just a tie rod. On one end, we have some all thread that will go into a rod end uh for our cyclic mixer that will control the pitch. And then the other end, we're going to cut to length uh where it needs to be, where it will line up with the stick. And we'll install a rod end on that end. And that will basically sum up this whole section.

[00:14:18][snorts] All right, that sums it up for the cyclic controls. Both the roll and the pitch have full travel. Those go all the way up to the swash plate and it also links the collective. Everything is complete. There is one other thing though. Right now, the swash plate, the non-rotating portion of the swash plate, uh, can actually rotate, and that's because currently there's nothing to inhibit that rotational motion. And that is where the anti-rotation plate comes into play. This is an 8 in piece of aluminum with a slot cut in the middle of it. I've gone ahead and designed some anti-wear plates to go on either side.

[00:15:21]They'll be eventually printed out of TPU, and they're secured on there with six 3 mm bolts. This plate gets mounted in the helicopter on the fuselage over the post that goes on the non-rotating side of the swash plate and it basically fixes the non-rotating assembly in the proper orientation to the fuselage which therein is the actual orientation of your controls. It's very important that it's aligned forward aft with the helicopter and only inhibits rotational moment and nothing in the up and down that being collective or uh actual forward or aft cyclic. So, as I'm fitting this up to drill the mounting holes, I'm going to be checking the full forward and down collective, which would put the post in the furthest down position, and then full back and up collective to make sure it's in the full top position to make sure I'm not getting any interference. From there, it's just marking the holes, drilling them, and installing the hardware.

[00:16:22]Getting the vertical position of this anti-rotation plate was pretty straightforward. But getting the lateral position and the inline position, I mean, nightmare. There's nothing really good to reference from. So, the best I got was I put a piece of tape at the front of the mast and I hung it down to the center portion of the base. And that should in theory be the straightest line for that axis. And then from there, I offset the hole spacing. Also, because the bottom two holes are easier to get to, I'm actually going to save those for last. And I'm going to get the top two drilled in where I think they should go.

[00:17:07]That way, I can basically match drill the lower two where it's easier to access. And I think that's going to get me where I need to be.

[00:17:25]Cali from the future here. Editing Cali made that whole process look way too easy and I call That was miserable. You can't get your hands in there to do anything. And I absolutely hated it. Wanted to set that record straight. While I'm here and keeping with the spirit of not leaving projects unfinished, I figured why not finish up the actual control stick. If you remember, I found an extra stinger. This goes at the back of the helicopter and protects the tail rotor. Uh, and this just happened to have the same bend radius and general dimension of what I modeled my 3D printed part out of. So, all we have to do now is make the real part look like the printed part, and we should be good to go.

[00:18:22]And would you look at that? It turned out exactly as planned. The clearance to the seat is basically perfect. Uh in the full app position and then in the full forward, it almost gets to the dash. Uh you have full travel all the way around.

[00:18:34]And I'd say it's pretty perfect. There are still three parts in here that are 3D printed. Those will all be replaced with aluminum. Fortunately for me, my uncle Buck is actually machining these pieces for me, and so I'll have them soon enough, and they will get swapped out. The last thing I want to get done on the inside of the helicopter is the foot pedals. Uh to start with that is this pivot post. This pivot post does have to come apart for future maintenance and for just installation, but the base needs to get permanently installed onto the helicopter. Uh, now because it does need to be disassembled periodically, I wanted a way to have a second form of retention because it is just a bolt and I don't want it to vibrate out. So, I drilled a hole through this base frame and through the bolt to put a cotter pin. That way, I have that second form of retention and it'll just make me sleep better at night. The base gets installed with five rivets. I'm going to lock it in with just one rivet for now. That way, if I decide I want to paint underneath it, I only have one rivet to drill out. And if I want to leave it in, it's just a matter of match drilling and then filling in the rest of those rivets.

[00:19:40]With the parts from the factory, when the tail rotor is in its neutral position, your toes are actually pointed pretty high. So, I'm attempting to get them lowered as much as possible. And in order to do that, uh, I had to trim off the end of the pedal, as you see here. I did the one side so you can actually see the comparison between both. Uh, and once again, the goal is to just get it as far forward as possible. I'll get the other foot pedal trimmed up, and we'll get the linkages installed, and that should be a wrap.

[00:20:24]Now that the controls are all together, I figured it'd be informative and cool to explain how all of this stuff works.

[00:20:30]There's a YouTube channel here called Bzig, and this is by far the most correct and informative source for information about the dynamics and mechanics of Rotocraft in general that I've ever stumbled across. Highly encourage you to go check that out.

[00:20:47]You'll learn a whole lot about Rotocraft. The controls of the Mosquito are more like an instrom helicopter where the controls go through the main shaft of the helicopter. Most helicopters, those controls go on the outside of that main shaft, but fundamentally they all operate in basically the exact same way. At the heart of every helicopter is the swash plate. The swash plate tells the helicopter exactly what to do, and it will mirror exactly what the swash plate does. So when the swash plate rolls left or right, the helicopter will also roll left or right and in the similar fashion of forward and aft following the swash plate forward and aft. Now if you need to raise just collective or all the pitch at the same time to get you to go vertically, you have to lift the swash plate uniformly up or down and maintain whatever cyclic pitch angle is also in that swash plate. That's also where the terms cyclic and collective come from.

[00:21:46]The cyclic is a cyclical motion that controls the blades cyclically as it rotates and controls the direction of the helicopter. And the collective uniformally or collectively raises the pitch of all the blades in the rotor system at the same time. Here you can see how just the roll is isolated where just the left and right roll tie rods are moving.

[00:22:11]And then for pitching up and down the top pitch bar, its forward aft motion is translated to a vertical motion with a bell crank. And that vertical motion tips the swash plate forward and aft for that pitch up and down. And then finally, you can see how the collective movement raises all three push rods without moving them at all to collectively add or reduce the pitch in the blades. That's a pretty simplified version about how all this works. It gets a lot more complicated once the head's on there and how it controls the actual blades, but I absolutely am fascinated by helicopter dynamics and mechanics. It's literally the reason that I wanted to build a helicopter in the first place. So, let me know in the comments if that's something you want to see. I'm happy to put that together. All of the parts are officially in the basement. And this is an engine. If you want to see more, make sure you subscribe. We're going to get this thing going. Go build something cool. Never stop learning. And we'll see you on the next one.